This add-on automatically creates links for predefined words or text in product's description.

Demo:
http://ocdemos.womgoo.com/index.php?route=product/product&product_id=31

Admin area:
http://ocdemos.womgoo.com/
user: demo
pass: demo

In admin area in Catalog -> Auto Links can be managed anchor words/text and links. You can add unlimited anchor words.

UPDATE:

You can set the target and you can add tool-tips.
SEO report is included for FREE.
Clear SEO is included for FREE.

VQMOD required. No files or data will be overridden.

This extension is included in Opencart SEO PACK PRO. It contains 20+ SEO related extensions and you can save more than $150 by purchasing the full Opencart SEO PACK PRO:

http://www.opencart.com/index.php?route=extension/extension/info&extension_id=6182


*** This extension is not compatible with OC 2.x. The version for OC 2.x and OC 3.x is included in Opencart SEO Pack PRO which also includes all the other SEO related extensions and features.